West of Lacunosa town has around lv 50-55 Pokemon, but are there higher level wild Pokemon anywhere else?
Kyurem is highest at lv.75 but going to him in Giant Chasm has shaking spots with lv.53-60 such as Audino, Ditto, Mamoswine, etc.
In some bubbling spots if you go fishing with a super rod you might just end up with a massive 70 leveled pokemon.